The Chemistry of Natural Dyes - Bytesize Science

the natural dyeing of textiles is an extremely easy and accessible way to transform that boring white tea into a landscape of vibrant natural hues it's really quite easy to do at home and there are tons of household items you can use in the process we recently visited the Brooklyn textile Art Center to get a demo on how to do it and we'll also explain some of the basic chemistry that's going on with the process along the way I'm Sahara Johnson I am an intern at textile Art Center in Brooklyn right now we're doing a demonstration on natural dyeing the process of this is taking natural things from the earth like fruits and vegetables different roots etc etc and taking the color from them and translating them into a fiber so right here I have silk that is being wetted um when you are doing natural dyeing you'd never want to directly put in a dry fiber into the dye bath it doesn't translate the color as well so right here I'm wetting it so right here is red cabbage it's one of my favorite things to dye with its really pH sensitive so it changes color really readily and right here is Coach nail which is actually not a plant it's a little bug found on cacti yeah and it's one of the most ancient forms of red um it's really really vibrant you'll see in a bit so with these two natural dyes red cabbage and cochineal there's one very big difference in how they work cabbage is what is called the substantive dye it contains a pigment called an anthocyanins which is water-soluble this means that the pigment molecule can directly bond to a natural fiber on its own cochineal on the other hand is known as an adjective dye adjective dyes requires something to stop the dye from washing out of a fiber cochineal is an anthraquinone dye which is a red dye that requires a bonding material called a mordant the mordanting process is when fibers are treated with the metal salt solution such as aluminum chromium copper iron or tin salts creating a lasting bond between the dye and the fiber the mordom basically allows the dye molecules to lock tightly with the fibers Sahara in this case is use a substance called alum for her in the co-channel diet this is a substance that's more commonly used in the kitchen for pickling say I wanted to get a lavender color rather than like a deep like royal purple I wouldn't necessarily leave this in for very long just put the whole thing in and then I'll do the coach nail on this one as we just learned red cabbage is an anthro sign and dye what's interesting about the color of anthocyanin pigment is that it's pH directly affects the range of its color by introducing an acid to this pigment anthocyanins will turn red by introducing a base it will turn more of a bluish green color at home you can add lemon juice to the dye as an acid or for a base you can use baking soda keep this in mind while dine with red cabbage you actually have a lot of colorful options right now I am taking out my dye matter I'm pretty satisfied with the color that has been extracted so I'm just taking this out to stop that process from happening so now I've strained out the cabbage from the dye bath there will be no more extraction happening and now I'm going to add my fiber I about good what's this I'm pretty content with this pink and this lavender so I'm going to take it out of the dye bath and I'm going to rinse it with water and pH neutral soap it's very important to remember that when rinsing your fiber of excess dye you have to use pH neutral soap such soaps are very common can be found at virtually every grocery store protip most pH neutral soaps completely clear if your soap is not neutral you will in fact alter the color of your fiber here is my lovely lavender silk yeah fun stuff and then we'll take out the coach Neal and yeah it's very spotted but I like it I think it's really beautiful now that you know the basics of natural dyes you can try it out at home with tons of different natural products one last thing to remember about these dyes is they do change color over time and can slowly fade or go through slight variations in color if you aren't happy with the color you can always just go back in and dye it again also you can try mixing dyes to produce a huge range of different colors so this is a really really easy process to do and that I encourage you all to try at home a lot of household items like they did the tumeric and the red cabbage can be found at your local grocery store anywhere so yeah everything is really accessible and definitely get to it you

Channel: BytesizeScience

Views: 312,689

Rating: 4.8385901 out of 5

Keywords: Chemistry, ACS, Science videos, American Chemical Society, Chemistry Demos, Research videos, Cochineal, red cabbage, natural dye, organic dye, turmeric, brooklyn textile arts center, cloth, acid, base, pH, adjective, substantive

Id: Gwk1B66dvAM

Length: 5min 29sec (329 seconds)

Published: Tue Oct 15 2013